Over at the Moms Who Blog Discussion Group, Helen asked about a "test blog." I shared the following steps for setting one up.
I use my test blog to play around with my template, to learn about html, and to save a few photos.
Your test blog can be set up so that it's not visible on your profile page, if you follow these instructions (on Blogger):
Set up your test blog, then, go to "Settings."
Under "Basic", select "No" for "Add your blog to our listings?"
Under "publishing" select "No" on "send pings?"
Under "permissions" select "Only blog authors" or "only people I choose" under "Blog readers."
Also, from your Dashboard, there is an option for editing your profile. You can check to make sure your test blog is invisible from there. Take a look at "Select Blogs to Display." If you've answered all of the above as noted, your test blog shouldn't even show up as an option there.
All of the above has worked for me to have a test blog that is visible on my dashboard, but not visible in my profile to the public.